Posts Tagged ‘power purchase agreement’

RATCH Australia (RAC 2013) in conjunction with the University of Queensland (UQ) are researching the feasibility of a hybrid gas-concentrated solar power (CSP) plant using Linear Fresnel Reflector (LFR) technology to replace the coal fired power station at Collinsville, Queensland, Australia. The project is supported by the Australian Renewable Energy Agency (ARENA) and administered by the Global Change Institute at UQ.

Both the gas generation and LFR technology are proven technologies and both boil water to drive a generator to produce power. The LFR uses ground level mirrors to concentrate the suns energy onto a higher re-concentrator mirror that focuses the energy onto a pipe containing water to produce steam for the generator, see Figure 1.

Figure 1: Concentrated Linear Fresnel Reflector

(Source: Novatec Solar 2014)

The combined gas-solar plant allows the plant to maintain a constant electricity output because the gas boiler operates when the sun does not shine. Table 1 shows the proposed electricity output by hour of week. This constant electricity power output during the week avoids the variability of solar generation, which allows the plant to operate as a baseload plant in a similar way to coal-fired power stations. Both the solar boiler and gas boiler can use the same generator therefore saving on capital investments. A team from the School of Mining and Mechanical Engineering are researching issues surrounding duel boiler use of the same generator (Singh & Gurgenci 2014). Another team is investigating techniques to keep the mirrors clean (Guan, Yu & Gurgenci 2014).

The transmission lines to connect a generator to the electricity grid can cost a million dollars or more a kilometre, therefore reusing the existing transmission lines at Collinsville is not only a major savings in capital investment but saves on producing CO2 emissions that would otherwise be required to produce the steel and other metals for connection to the grid. A team from the School of Information Technology and Electrical Engineering are researching grid stability issues (Shah, Yan & Saha 2014).

This project provides a template for future hybrid schemes because Australia’s ageing coal-fired power stations are close to retirement and their grid connections will become available to similar renewable schemes. The hybrid schemes also allow the transition and retraining of fossil people into renewable people.

A team from the Energy Economics and Management Group, School of Economics is forecasting the lifetime yield of the solar plant (Bell, Wild & Foster 2014b) and revenue and dispatch of the plant (Bell, Wild & Foster 2014a). These forecasts both help determine the financial feasibility of the plant and help secure a power purchase agreement for the power produced. Seven ‘Collinsville solar thermal project’ reports are due for publication in November or December this year; the draft reports were due in May this year. Please correspond with the authors if you have any questions.